1. Got a mast and sails? It's either a SV or a MSY - take your pick.
2. No such thing as right of way at sea. For whether they are "stand on" or "give way", it depends on the circumstances. They are a sailing vessel when under sail, a motor vessel when under motor.
COLREGs
Rule 3
(b) The term “power-driven vessel” means any vessel propelled by machinery.
(c) The term “sailing vessel” means any vessel under sail provided that propelling machinery, if
fitted, is not being used.
What lights you display will depend on whether you are motoring or not. You need to have your navigation lights set up so that you can display the appropriate lights both when under sail and when under motor.